The manufacturing sequence of a semiconductor device includes a film forming process of forming a nitride film, such as a silicon nitride film (SiN film) or the like, as an insulation film, on a semiconductor wafer, namely, a silicon wafer. Chemical vapor deposition (CVD) is widely used in a SiN film forming process.
Recently, in terms of improving properties along with the progress of miniaturization and high integration of a semiconductor device, a method of forming a SiN film by sequentially supplying gases, such as atomic layer deposition (ALD), which is capable of forming a high-quality film at a temperature lower than that in conventional CVD, has been conducted. In case of forming a SiN film by ALD, a SiN film having a predetermined thickness is formed by repeating the following steps a predetermined number of times: adsorbing a Si raw material onto a substrate to be processed; and subsequently supplying a nitriding gas to react with the Si raw material, thereby forming SiN at an atomic layer or at a molecular layer level.
As a method of forming a SiN film by means of ALD, there has been proposed a technology for alternately supplying a dichloro silane (DCS; SiH2Cl2) gas as a Si raw material gas and an ammonia (NH3) gas as a nitriding gas, wherein plasma is generated by applying high-frequency power when supplying the NH3 gas, thereby accelerating nitriding reaction.
Furthermore, since the configuration of an apparatus becomes complicated when using plasma, forming a SiN film by sequentially supplying gases without using plasma, as in thermal ALD, has been considered.
However, when growing the nitride film such as an SiN film on a structure in which two or more types of different base films are exposed by ALD or CVD, it has been necessary to selectively grow the nitride film on a specific base film.